1. Technical Field
This present invention relates generally to devices using dynamic therapeutic movement and strengthening for rehabilitation of the ankle, knee and hip with variability from non-weight bearing to full weight bearing force.
2. Description of the Related Art
The importance of therapeutic exercise is widely accepted for a variety of human disabilities. Exercise plays a crucial role in the rehabilitation of patients suffering from various injuries. Physical therapists regularly provide rehabilitative professional care that individually tailors exercise programs to meet a patient""s needs. Rehabilitative exercise programs differ depending on the type and amount of damage to the injured area, stage of tissue healing, age of the person, and prior level of function of the individual prior to injury.
In many cases, lack of exercise is a contributing factor, if not the primary predisposing factor influencing injury in an adult. The human body was meant to move. As people get older they move less and sit more. Movement increases blood supply which facilitates greater nutrients to muscle and bone and maintains the health of the living tissue. In particular, the meniscus of the knee is considered an avascular structure and obtains most of its nutrients via the synovial fluid within the joint capsule. Movement of the knee is vital to the distribution of those nutrients. The lack of movement results in poor distribution of nutrients and tissues becomes weaker and more susceptible to injury.
The importance of early movement and strengthening to the recovery of hip, knee and ankle injuries is widely accepted. In particular, studies have shown that people who have undergone ACL reconstructive surgery and have started early movement have fared better than those of the past in which rest and fixation of the knee were thought to be the best approach. Physical therapists regularly provide rehabilitative professional care to individuals who are recovering from hip, knee and ankle injuries. A goal in all hip and knee injuries whether post surgical or non-surgical, is to get early pain free movement. A common limitation with rehabilitation of post surgical knee and hip patients is the restriction of weight bearing. Weight bearing restrictions may vary in time frames from one day post-operative to twelve weeks of limited weight bearing status. The amount of weight bearing and how early weight bearing can start depends on the surgery or trauma to the tissue. Weight bearing status may range from xe2x80x98toe-touchxe2x80x99 to xe2x80x98partial weight bearingxe2x80x99 xe2x80x98to weight bearing as toleratedxe2x80x99 and, finally, xe2x80x98full weight bearingxe2x80x99 with or without restriction for rotational movements.
The most common early rehabilitation methods consist of isometric exercise, Continuous Passive Motion (CPM) machines and or active assisted range of motion (ROM) performed by a therapist on a patient. Isometric exercise is a good way to initiate strength into newly repaired tissue but the benefits are limited to the point in the ROM that the exercise takes place and does not generally facilitate movement in post-operative rehabilitation. The return to normal or pre-surgical levels of movement has long been heralded one of the most important achievements in recovery and many people have proposed that the use of CPMs help achieve that goal the best. There is a CPM that has utilized movement facilitation through the femur instead of the foot, yet there is no definitive study that demonstrates either the traditional CPM or the newer model that avoids compressive forces is truly the most beneficial form of rehabilitation of hip and knees.
A third common means for obtaining strength and movement in post surgical or post traumatic injuries to the knee or hip is ROM performed by a physical therapist. The biggest restriction with this approach is that therapy is labor intensive, costly and infrequent. The techniques used by physical therapists to establish and/or maintain ROM is either passive ROM or active assisted ROM. Active assisted ROM is usually instituted after a certain time for healing to occur or pain has decreased with contraction of the muscles. The limited exercises given to patients at present for their home program consist usually, but not solely, of isometric muscle setting exercises to the gluteal and quadriceps muscles. These exercises do not involve joint movement. Exercises that are usually instituted later in the rehabilitation process utilize a resistive band and may provide less stability to the joint and are generally less comfortable, therefore, usually yield less patient compliance. Finally, patients are given a variation of exercises that involve open and closed chain activity. These can place an unwanted compressive or shear force on the joints.
CPM movement is completely passive and the patient does not physiologically control the movement. Although movement is occurring at the joint, muscle atrophy can persist and poor motor control may result.
Regular exercise may keep the body in good shape, but not all exercise is equally effective. In fact, many exercise devices on the market, particularly in health and athletic clubs, are less effective than people realize. That is not to say that the majority of the exercise equipment in health clubs is not beneficial under guidance by a trainer. Most available equipment in health clubs train in predominantly linear, single plane movement and is limited to isolating one muscle group while allowing other muscle groups to rest. Examples of this type of exercise can be put into two categories: the first is the leg press, a closed chain activity; the second exercise is the leg extension which is an open chain exercise and generally not considered ideal for knee or hip rehabilitation. This type of training may be appropriate in an athlete or one who has a balanced workout regimen, but isolated, open chain, planar movement is not how the body typically moves.
The body rarely moves in just one plane and often requires multiple muscle groups to work together. Most body movement involves rotation and diagonal patterns of movement. Imagine trying to without any arm swing or trunk rotation. Think of taking off a sweatshirt or pulling on a pair of socks with linear single planar movementxe2x80x94difficult? Yes! Taking a step requires combined movements of plantar flexion, internal hip rotation, foot pronation/supination, knee extension and hip extension. If we moved in single planes it would be easy to construct a mechanical hand, foot or leg to mirror human movement, but it is very difficult to replicate human movement because it is not defined through one or two dimensional movement. The myriad of muscles surrounding our joints allow us to move in limitless but controlled patterns.
Proprioceptive Neurofacilitation, PNF, is a school of thought within physical medicine that believes the best form of rehabilitation for musculoskeletal injuries occurs in diagonal patterns through multiple planes of movement. However, this treatment technique requires a purely hands-on, manual approach, extremely demanding of therapist skill and training. The therapist presently practicing PNF must take the patient through the motions and provide appropriate resistance for the patient""s need and present physical limitations. There is a need in the exercise equipment art, therapeutic or not, for an apparatus that provides structured, multiaxial, multi-pattern movement to the average healthy person or to someone recovering from hip, knee or ankle injury that would allow the patient to control for different muscle patterns.
While the prior art provides attempts at developing equipment that embodies movement components of rotational and diagonal non-liner exercise, in many cases, these are smaller replicas of machines found in many fitness centers. In fact, to my knowledge, there are few portable lower extremity machines that have attempted to provide a source of rehabilitation for those patients who have limited mobility and may only be able to exercise from a bed or chair. The Mini gym, is a portable apparatus that simulates the closed chain activity of a leg press. The device provides no support for the hip or knee and the only form of resistance is provided through the feet. There is no way to control for ankle inversion, eversion plantar or dorsiflexion. It is primarily a linear form of resistance that applies its force and load along the long axis of the bones, thus, any increase in resistance is going to approximation the joint and increase weight bearing forces. There is another piece of exercise equipment that has recently hit the exercise market and is targeting quick, portable exercise to shape the inner and outer thighs, abdominal and the gluteal muscles. The Beautiful U_ requires the person hold the apparatus as they exercise. This may be very limiting for patients with a strokes or less limber patients who are in a lot of pain after surgery. The location of force application is similar to the beautiful U_, but said apparatus does not require the user to hold it. Unlike the beautiful U_ with a rigid single dimension resistance, the present invention has a supple sling like rest that will contour to the user""s leg and allow for lateral and diagonal movements. The Beautiful U_ only provides resistance in one plane, the present invention can provide variable directions of resistance at once.
The present invention, provides its resistance force perpendicular to the long axis of the femur or tibia, thus, providing an apparatus that facilitates simultaneous hip and knee movement similar to closed kinetic chain exercise without the compressive forces of weight bearing. It is hypothesized that it will also reduce the shear force usually encountered during open chained exercise. This apparatus also allows for an additional force of joint distraction. Said apparatus can also stimulate dorsiflexion or plantar flexion simultaneously with hip and knee extension. No other prior art demonstrates resistance to hip extension simultaneous with dorsiflexion or plantar flexion. In this day of managed care in which treatment is limited it is most important to provide a portable exercise apparatus. This is particularly important in acute care settings where patients cannot get out of their bed. The portability is also valuable to the versatility of the device to be used in sitting, standing, kneeling or lying in a supine position during bed rest.
Another device, illustrated in U.S. Pat. No. 5,279,530, attempted to exercise the lower extremity in a supine position. The disadvantages of this machine include: only linear movement; no rotational component. Moreover, the most significant embodiment of this device involves exercise of only the lower extremities and only in a supine position.
It would therefore be of significant value in the art to provide a device enabling a user to obtain multidimensional exercise that provides multiple embodiments and would allow the user to progress toward full rehabilitation by isolating the difficulty and complexity of movement. Healthy, as well as, injured users could benefit from a device that trains the extremities and the trunk musculature in an unloaded position.
A first object of the present invention is therefore to provide an improved exercise device which obviates or mitigates at least one of the aforementioned disadvantages of available devices.
In its broadest scope, the present invention provides a device that encourages multiple axes of muscle control while controlling for compressive joint forces. It allows exercise to occur in a horizontal position in which there is no axial loading of the joints. A compressive component may be added by utilizing the foot/ankle means of resistance. This means of resistance may be used to facilitate joint compression or add a component of joint distraction. Said apparatus may also be used with the person in a standing position as a final progression ending with total weight bearing. This device allows for much earlier rehabilitation than most of the prior art has revealed.
A specific embodiment provides a resistance means to the lower extremity that does not involve compressive joint force beyond that of a muscle contraction. A second specific embodiment minimizes shearing forces on the knee during resisted knee extension. A third specific embodiment facilitates rotation about the femur, not just straight hip/knee extension, via femoral means of resistance. The rotational component is important because the stance phase requires hip internal rotation with hip extension. A fourth specific embodiment provides for active assisted ROM for knee, hip and ankle movement. A fifth specific embodiment provides a multitude of combined resistance patterns, including but limited to: hip and knee flexion and extension, hip internal/external rotation and ankle dorsiflexion, plantar flexion, eversion and inversion.
In a more particular embodiment the person""s position is one defined as a xe2x80x9cquadrupedxe2x80x9d position with one lower extremity utilizing one or both means of resistance in the aforementioned combination of patterns. A person may also utilize said device prone on their stomach with one lower extremity utilizing one or both means of resistance in the aforementioned combination of patterns.